import math

def dot(a, b):
    sum=0
    c=zip(a,b)
    for item in c:
        sum+=item[0]*item[1]
    return sum

def mo(a):
    sum = 0
    for i in a:
        sum+=i*i

    return sum**0.5

def angle(a, b):
    ji=dot(a,b)
    amo=mo(a)
    bmo=mo(b)
    cos=ji/(amo*bmo)
    hudu=math.acos(cos)
    jiaodu=hudu*180/math.pi
    return jiaodu
